This invention relates in general to trolley-hung closures and other devices, and more particularly to a latching mechanism for securing the same.
Large doors, such as the type one might expect to find on barns or warehouses or industrial buildings; are commonly suspended from overhead tracks by means of trolleys which roll along those tracks. The typical door of this character thus slides or moves from closed position in which it covers an opening in a wall to an open position where it is located to the side of the opening. The track of course extends along the top of the opening as well as to the side of it, and the trolleys move along the track as the door is shifted from one position to the other. Trolley-hung doors are particularly suited for closing relatively wide openings which cannot be accommodated by a single hinged door, or even multiple hinged doors--opening which are large enough to accommodate wheeled vehicles without disruptive floor tracks or thresholds beneath them. Thus, trolley-hung doors find widespread use on barns, equipment buildings, warehouses, factories, and even for gates along roadways.
While trolley-hung doors possess clear advantages over hinge-mounted doors where large openings exist, they are not nearly as easy to secure as hinged-mounted doors. In this regard, the typical hinge-mounted door is secured with a bolt which projects from the free vertical edge of the door into the strike jamb of the surrounding door frame, that is into the jamb along which the free edge lies when the door is closed. Since trolley-hung doors move along the opening toward and away from the strike jamb, a simple bolt will not secure it to the strike jamb. Latches and keepers have been developed for engaging trolley hung doors with their strike jambs, but this type of latch protrudes from the edge of the door and the keeper may project from the door jamb, so both present hazards along the sides of the door opening--hazards which might prove harmful to people, animals, or vehicles passing through the opening. For example, a keeper along the side of a barn door opening could snag the flesh of a farm animal, such as a cow or horse, passing through the opening. Another popular mechanism for securing trolley-hung doors is the floor or head bolt which operates vertically, engaging a keeper along the bottom or top of the door opening. These devices present alignment problems, for if the bolt does not align precisely with its keeper--which is quite possible given the size of the doors for which they are designed--the door remains unsecured. Furthermore these devices are not easy to install, for they require some type of aperture along the top or bottom of the door opening and installation with enough precision to enable the bolt to align with the aperture.
The latching mechanism of the present invention lies along the track of the trolley-hung door, indeed with the latch being carried by one of the trolleys and the keeper by the track. The two align precisely, because the track confines the trolley and allows little displacement laterally or vertically in contrast to the much larger and heavier door. Moreover, the device is installed without any special preparations to or installations on the door or the door frame.